diff options
Diffstat (limited to 'wozmon.s')
| -rw-r--r-- | wozmon.s | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/wozmon.s b/wozmon.s new file mode 100644 index 0000000..4fd7d10 --- /dev/null +++ b/wozmon.s @@ -0,0 +1,208 @@ +ACIA_DATA = $5000 +ACIA_STATUS = $5001 +ACIA_CMD = $5002 +ACIA_CTRL = $5003 + +XAML = $24 ; Last "opened" location Low +XAMH = $25 ; Last "opened" location High +STL = $26 ; Store address Low +STH = $27 ; Store address High +L = $28 ; Hex value parsing Low +H = $29 ; Hex value parsing High +YSAV = $2A ; Used to see if hex value is given +MODE = $2B ; $00=XAM, $7F=STOR, $AE=BLOCK XAM + +IN = $0200 ; Input buffer + +RESET: + CLD ; Clear decimal arithmetic mode. + CLI + LDA #<CHRIN + STA $FFFE + LDA #>CHRIN + STA $FFFF + LDA #$1F ; 8-N-1, 19200 bps + STA ACIA_CTRL + LDY #$8B ; No parity, no echo, no interrupts. + STY ACIA_CMD + +NOTCR: + CMP #$08 ; Backspace key? + BEQ BACKSPACE ; Yes. + CMP #$1B ; ESC? + BEQ ESCAPE ; Yes. + INY ; Advance text index. + BPL NEXTCHAR ; Auto ESC if line longer than 127. + +ESCAPE: + LDA #$5C ; "\". + JSR ECHO ; Output it. + +GETLINE: + LDA #$0D ; Send CR + JSR ECHO + LDA #$0A ; Send LF + JSR ECHO + + LDY #$01 ; Initialize text index. +BACKSPACE: DEY ; Back up text index. + BMI GETLINE ; Beyond start of line, reinitialize. + +NEXTCHAR: + LDA ACIA_STATUS ; Check status. + AND #$08 ; Key ready? + BEQ NEXTCHAR ; Loop until ready. + LDA ACIA_DATA ; Load character. B7 will be '0'. + STA IN,Y ; Add to text buffer. + JSR ECHO ; Display character. + CMP #$0D ; CR? + BNE NOTCR ; No. + + LDY #$FF ; Reset text index. + LDA #$00 ; For XAM mode. + TAX ; X=0. +SETBLOCK: + ASL +SETSTOR: + ASL ; Leaves $7B if setting STOR mode. +SETMODE: + STA MODE ; $00 = XAM, $74 = STOR, $B8 = BLOK XAM. +BLSKIP: + INY ; Advance text index. +NEXTITEM: + LDA IN,Y ; Get character. + CMP #$0D ; CR? + BEQ GETLINE ; Yes, done this line. + CMP #$2E ; "."? + BCC BLSKIP ; Skip delimiter. + BEQ SETBLOCK ; Set BLOCK XAM mode. + CMP #$3A ; ":"? + BEQ SETSTOR ; Yes, set STOR mode. + CMP #$52 ; "R"? + BEQ RUNPROG ; Yes, run user program. + STX L ; $00 -> L. + STX H ; and H. + STY YSAV ; Save Y for comparison + +NEXTHEX: + LDA IN,Y ; Get character for hex test. + EOR #$30 ; Map digits to $0-9. + CMP #$0A ; Digit? + BCC DIG ; Yes. + ADC #$88 ; Map letter "A"-"F" to $FA-FF. + CMP #$FA ; Hex letter? + BCC NOTHEX ; No, character not hex. +DIG: + ASL + ASL ; Hex digit to MSD of A. + ASL + ASL + + LDX #$04 ; Shift count. +HEXSHIFT: + ASL ; Hex digit left, MSB to carry. + ROL L ; Rotate into LSD. + ROL H ; Rotate into MSD's. + DEX ; Done 4 shifts? + BNE HEXSHIFT ; No, loop. + INY ; Advance text index. + BNE NEXTHEX ; Always taken. Check next character for hex. + +NOTHEX: + CPY YSAV ; Check if L, H empty (no hex digits). + BEQ ESCAPE ; Yes, generate ESC sequence. + + BIT MODE ; Test MODE byte. + BVC NOTSTOR ; B6=0 is STOR, 1 is XAM and BLOCK XAM. + + LDA L ; LSD's of hex data. + STA (STL,X) ; Store current 'store index'. + INC STL ; Increment store index. + BNE NEXTITEM ; Get next item (no carry). + INC STH ; Add carry to 'store index' high order. +TONEXTITEM: JMP NEXTITEM ; Get next command item. + +RUNPROG: + JMP (XAML) ; Run at current XAM index. + +NOTSTOR: + BMI XAMNEXT ; B7 = 0 for XAM, 1 for BLOCK XAM. + + LDX #$02 ; Byte count. +SETADR: LDA L-1,X ; Copy hex data to + STA STL-1,X ; 'store index'. + STA XAML-1,X ; And to 'XAM index'. + DEX ; Next of 2 bytes. + BNE SETADR ; Loop unless X = 0. + +NXTPRNT: + BNE PRDATA ; NE means no address to print. + LDA #$0D ; CR. + JSR ECHO ; Output it. + LDA #$0A ; LF. + JSR ECHO ; Output it. + LDA XAMH ; 'Examine index' high-order byte. + JSR PRBYTE ; Output it in hex format. + LDA XAML ; Low-order 'examine index' byte. + JSR PRBYTE ; Output it in hex format. + LDA #$3A ; ":". + JSR ECHO ; Output it. + +PRDATA: + LDA #$20 ; Blank. + JSR ECHO ; Output it. + LDA (XAML,X) ; Get data byte at 'examine index'. + JSR PRBYTE ; Output it in hex format. +XAMNEXT: STX MODE ; 0 -> MODE (XAM mode). + LDA XAML + CMP L ; Compare 'examine index' to hex data. + LDA XAMH + SBC H + BCS TONEXTITEM ; Not less, so no more data to output. + + INC XAML + BNE MOD8CHK ; Increment 'examine index'. + INC XAMH + +MOD8CHK: + LDA XAML ; Check low-order 'examine index' byte + AND #$07 ; For MOD 8 = 0 + BPL NXTPRNT ; Always taken. + +PRBYTE: + PHA ; Save A for LSD. + LSR + LSR + LSR ; MSD to LSD position. + LSR + JSR PRHEX ; Output hex digit. + PLA ; Restore A. + +PRHEX: + AND #$0F ; Mask LSD for hex print. + ORA #$30 ; Add "0". + CMP #$3A ; Digit? + BCC ECHO ; Yes, output it. + ADC #$06 ; Add offset for letter. + +ECHO: + STA ACIA_DATA ; Output character. + PHA ; Save A. +; LDA #$FF ; Initialize delay loop. +; TXDELAY: DEC ; Decrement A. +; BNE TXDELAY ; Until A gets to 0. + PLA ; Restore A. + RTS ; Return. + +CHRIN: + RTI + +CHROUT: + pha + sta ACIA_DATA +; lda #$FF +; .txdelay: dec +; bne .txdelay + pla + rts + |